1. Field of the Invention
The present invention relates to a method and an apparatus for controlling an electromagnetic driving valve for an internal combustion engine for use as an intake and exhaust valve in an internal combustion engine, and more specifically to the electromagnetic valve driving control technology in starting the engine.
2. Description of the Prior Art
It has been conventionally known that an electromagnetic valve is designed to displace an intake and exhaust valve supported in a neutral position with elasticity using a spring between an all-closed position and an all-opened position by using the electromagnetic force. Furthermore, various methods such as a starting sequence, etc. have been disclosed for starting control of an electromagnetic valve for use in starting an engine.
In the method of starting an electromagnetic valve, as described in Japanese Patent Laid-Open No. 9-303122, an electromagnetic valve initially in the neutral position is normally started by exciting the intrinsic vibration of a spring mass system of the electromagnetic valve for displacement to the all-closed position or the all-opened position. In this case, unlike opening or closing a mechanical cam, starting control is required.
Japanese Patent Laid-Open No. 9-303122 discloses an example of starting control of an electromagnetic valve to be started by setting the starting time of an electromagnetic valve in an area of a crank angle, at which the time required for the electromagnetic valve started for excitation to reach the all-closed position and maintain the position can be shorter than the time required for a piston to reach the position of the interference caused by the body of the electromagnetic valve by the rotation of the crank shaft, so that the excited electromagnetic valve cannot come in conflict with the piston after starting the cranking of an engine.
Furthermore, Japanese Patent Laid-Open No. 2000-97059 discloses an example of starting control of an electromagnetic valve by, unlike the above mentioned example, displacing the electromagnetic valve to the all-opened position when the ignition switch is turned on, then the cranking of the starter motor is started, and the all-opened state of the electromagnetic valve is maintained until the number of cranking rotations reaches the reference number of rotations to reduce the compressing operation during the cranking process.
Object of the Invention
However, in the example of the above mentioned Japanese Patent Laid-Open No. 9-303122, as pointed out in Japanese Patent Laid-Open No. 2000-97059, a very large compressing operation occurs immediately after the all-closed state is entered depending on the crank angle at which the intake and exhaust valve is all closed in the method of displacing the intake and exhaust valve to the all-closed position during the cranking process. Therefore, a starter motor durable of the compressing operation is required. That is, a starter motor controlled by an inverter is limited in output torque by the capacity of the power element. As a result, an internal combustion engine only having such a starter cannot be satisfactorily used.
Furthermore, in the example of the above described Japanese Patent Laid-Open No. 2000-97059, the electromagnetic valve is maintained in the all-opened position before the starter motor is turned on. Therefore, by the influence of the rushing current immediately after the starter motor is turned on, the support of the electromagnetic valve can possibly be removed. In addition, if the cranking process is performed with the valve opened, the interference between the intake and exhaust valve and the piston cannot be avoided as pointed out by the above described Japanese Patent Laid-Open No. 9-303122, thereby requiring a recess in the piston to avoid the interference. Furthermore, when the cranking process is performed with the valve opened, a pumping loss occurs.
The present invention has been developed to solve the above mentioned problems, and aims at obtaining a method and an apparatus capable of starting an engine with a starter motor having a small output torque, and controlling the electromagnetic valve for an internal combustion engine not requiring a recess in the piston.
A method for controlling an electromagnetic driving valve for an internal combustion engine according to claim 1 of the present invention includes the steps of: starting cranking a crank shaft by a starter; sequentially starting the excitation of intake and exhaust valves such that the valve can be all closed at a predetermined crank angle after the rotating speed of the crank shaft has reached a first predetermined rotating speed; starting switching control of an intake and exhaust valve according to the normal process of each cylinder under the condition of the above mentioned intake and exhaust valve closed, and the rotating speed of the crank shaft exceeding a second predetermined rotating speed; and transferring to normal control.
The method for controlling the electromagnetic driving valve for the internal combustion engine according to claim 2 of the present invention sets the above mentioned predetermined crank angle so that the valve closing crank angle of the last closed electromagnetic driving valve in at least each cylinder can indicate substantially equal values between the compressed task amount and the expanded task amount from the crank angle.
The method for controlling the electromagnetic driving valve for the internal combustion engine according to claim 3 of the present invention includes the step of prohibiting power supply to the starter from the starting time of closing valve to the ending time of closing valve for the electromagnetic driving valve.
The method for controlling the electromagnetic driving valve for the internal combustion engine according to claim 4 of the present invention includes the step of amending the first predetermined rotating speed based on the level of the load of the engine.
The method for controlling the electromagnetic driving valve for the internal combustion engine according to claim 5 of the present invention includes the step of computing the necessary output to the starter to drive the load of the engine, and the step of driving the starter based on the computed output from the starting time of closing valve to the ending time of closing valve for the electromagnetic driving valve.
In the method for controlling the electromagnetic driving valve for the internal combustion engine according to claim 6 of the present invention, the normal switching control of the intake and exhaust valve starts with an exhausting process.
The apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 7 of the present invention supports the intake and exhaust valve in the neutral position with elasticity using an elastic material, and displaces the intake and exhaust valve into the all-closed position or the all-opened position using the electromagnetic force. The apparatus includes: rotating speed detection means for detecting the rotating speed of a crank shaft based on the output of a crank angle sensor; and start control means for controlling an intake and exhaust valve such that the intake and exhaust valve can maintain its all-closed status at a predetermined crank angle after the rotating speed of the crank shaft has reached a first predetermined rotating speed set in advance depending on the necessary task amount required to make a rotation of the crank shaft after the inertia around the crank shaft and the intake and exhaust valve has entered the all-closed state. With the configuration, the switching control of the intake and exhaust valve is started depending on the normal process of each cylinder with the intake and exhaust valve maintained in its all-closed position, and the rotating speed of the crank shaft exceeding a second predetermined rotating speed.
The apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 8 of the present invention sets the above mentioned crank angle so that the valve closing crank angle of the last closed electromagnetic driving valve in at least each cylinder can indicate substantially equal values between the compressed task amount and the expanded task amount from the crank angle.
The apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 9 of the present invention includes first starter control means for prohibiting power supply to the starter from the starting time of closing valve to the ending time of closing valve for the electromagnetic driving valve.
The apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 10 of the present invention includes: load detection means for detecting the level of the load of an engine; and target rotation speed amendment means for amending the first predetermined rotating speed based on the level of the load.
The apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 11 of the present invention includes: load drive computation means for computing the necessary output to the starter to drive the load; and second starter control means for driving the starter motor based on the computed output of the load drive computation means.
In the apparatus for controlling the electromagnetic driving valve for the internal combustion engine according to claim 12 of the present invention, the normal switching control of the intake and exhaust valve is started with the exhausting process.